In electrophotographic imaging devices that form images by overlaying a plurality of planes to form the images, the degree of alignment between the overlaid planes can affect the perceived quality of resulting images. A need exists for a method and apparatus to improve the alignment between overlaid planes.
An alignment apparatus for use in an electrophotographic imaging device includes a first counter to count a first value of changes of a first signal, with the first value related to a first location of a photoconductor in a first direction. In addition, the alignment apparatus includes a second counter to count a second value of changes of a second signal, with the second value related to a second location of the photoconductor in a second direction substantially perpendicular to the first direction. Additionally, the alignment apparatus includes a circuit coupled to the first and the second counter to generate a change in a third signal after the first and the second counter count to, respectively, the first value and the second value.
A method includes changing a first count responsive to transitions of a first signal and changing a second count responsive to transitions of a second signal. Furthermore, the method includes generating a transition in a third signal after changing the first count a first value of times and after changing the second count a second value of times, with the first value related to a first location of a photoconductor in a first direction and with the second value related to a second location of the photoconductor in a second direction substantially perpendicular to the first direction.